smart objects rendering inside image alpha channels as layercoms maybe

Would be nice if after dropping an image file as a linked smart object  for example  we could get immediate access not only to RGB of that file  but to alpha channels  too.    Maybe as auto generated layercomps or something    or perhaps  having not only RGB checkboxes in a layer style/ blending options but  A too.    It's possible in Affinity photo for example with its procedural live filter